(1) Field of Invention
The present invention relates generally to hearing protective devices, and more particularly to a hearing protective device including two attenuating elements connected by a knotted cord and a method of manufacturing the hearing protection device.
(2) Description of Related Art
The use of hearing protective and noise attenuating devices is well known, and various types of devices are available including, but not limited to, ear muffs, semi-aural devices, and earplugs. Earplugs are particularly preferred for their effectiveness in attenuating sound and for comfort properties provided thereby.
An earplug generally comprises a sound attenuating element which is placed in the ear canal of a wearer to provide desired sound attenuation. The sound attenuating element is commonly made of a resilient foam material or a flexible, rubber-like material.
Several types of earplugs are known. A roll-down type earplug typically has a resilient foam body which is rolled by a user to reduce a diameter thereof. A portion of the reduced diameter earplug body is then inserted in the ear canal and allowed to expand therein to fill the canal and provide desired attenuation. The remaining portion of the earplug body extends from the ear canal and provides a handle for removing the plug. A push-in stem type earplug, as shown for example in FIG. 7, includes a resilient body 2 having a rigid or semi-rigid stem 4 embedded therein and, most typically, extending therefrom. The stem provides a degree of rigidity to the earplug which facilitates insertion of the plug body into the ear canal. During use, the exposed stem portion of the push-in stem earplug extends from the ear canal, thus providing a handle for removal of the earplug.
Earplugs often include a cord that attaches a pair of plugs and extends therebetween. See FIG. 1 in which earplugs 10 are shown connected by a cord 12. The cord 12 allows a user to hang the earplugs around their neck or elsewhere when the plugs are not being used. Also, the cord permanently relates a certain pair of earplugs and prevents against loss thereof.
Conventional cords are commonly designed so that the cord may be permanently attached to the earplugs and more specifically, each end of the cord may be permanently attached to ends of the earplugs. In the case of roll-down type earplugs, a cord is attached to one end of the resilient body. Push-in stem type earplugs generally have the cord attached at the exposed portion of the stem. Cords may be attached to the various types of earplugs, for example, by sonic welding or by adhesive bonding.
Corded earplug pairs are often sold in individual packages. For example, a single pair of earplugs attached by a cord are enclosed in a small plastic sealed package. A user acquires the package and opens the same to access the corded earplug pair. In this way, an individual pair of earplugs is conveniently provided to a user while a sanitary condition of the plugs in the sealed package is maintained.
Several methods of assembling and packaging the corded earplug pairs are known. With reference to FIGS. 1-4, the cord 12 is first manufactured and then wound in a spiral fashion so as to form a circular shaped bundle 14. Then a plastic clip 16 may be applied to the cord bundle to retain the circular shape thereof. Particularly, the plastic clip 16 is similar, if not identical, to plastic clips commonly used to maintain closure of bread bags. Once the cord 12 is clipped, the bundle 14 is positioned for connection with the earplugs 10. The two ends of the cord 12 are each attached to respective ends of each of the earplugs 10. As mentioned above, attachment may be made through a welding or adhesive bonding process. The corded earplugs 10 with the clipped cord 12 are then inserted into a waiting package 18 and the package 18 is sealed. The package 18 is, for example, a small plastic bag having an opening 20.
During packaging of the corded plugs, the clip is kept fastened to the cord bundle to maintain a compactness thereof and to prevent the cord from unwinding during or prior to packaging. The more compact the cord bundle, the less packaging material is required thus reducing material costs. Compactness of the cord bundle during packaging is also advantageous in facilitating insertion of the bundle into the package, i.e. a tight, compact cord bundle is much easier to pass through the opening of the package then a loose or unraveling cord bundle.
However, the plastic clip used to maintain the compact cord bundle is itself a separate product which increases the overall cost of the packaged corded earplug pair. Additionally, use of the plastic clip necessitates an additional step in the corded earplug assembly and packaging process. Further, the clip occupies valuable space within the packaging, thus the package must be slightly oversized to accommodate the clip. Accordingly, waste and disposal of the packaged clipped earplug is significant considering the additional piece of the clip and the required size increase of the package. Finally, the clipped cord is inconvenient for an end user since the clip must be manually removed prior to donning the earplugs. Further, the removal of the clip may threaten the integrity of the cord in that the plastic clip may contain sharp edges which can score the cord upon removal.
Referring now with particularity to FIG. 3, a paper wrap 22 has also been used to retain the cord bundle 14 in place of the plastic clip 16. The paper wrap 22, which is similar to a shoestring wrap or a light tape material, is wrapped around the spiral wound cord bundle 14 to retain the compact circular shape thereof. Then, the earplugs 10 are fixed to respective ends of the wrapped cord 12 and the corded pair is inserted into the waiting package 18.
Similar to the plastic clip, the paper wrap facilitates packaging of the corded earplug pair by maintaining the cord in a tightly wound, compact form and preventing against unraveling of the cord during or prior to insertion of the cord into the package. However, as with the plastic clip, the paper wrap is an additional item which increases the overall cost of the packaged earplugs, necessitates an additional step in the assembly process of the corded plugs, and requires the end user to incur the inconvenience of removing the paper wrap prior to unraveling the cord. Further, the paper is an additional piece which must be discarded by the end user, thus raising environmental and disposal concerns.
Referring now particularly to FIG. 4, it has also been attempted to assemble and package corded earplug pairs without utilizing a cord retaining device such as the plastic clip or paper wrap discussed herein above. In such a process, the cord 12 is first wound in a spiral to form the circular shaped cord bundle 14. The frictional properties of the cord 12 material are relied upon to retain the cord 12 in this wound position. The wound cord bundle 14 is then inserted in a waiting package. However, the cord 12 does not consistently remain in the wound bundle position, often coming unwound during or just prior to insertion of the cord bundle into the package. Further, compactness of the cord bundle is not obtained in this process requiring a larger package, thus increasing associated costs and again raising disposal and environmental concerns.
Accordingly, there remains a need for a corded earplug pair which may be efficiently and economically assembled and packaged and which may be readily accessed and used by a user.